A helical resonator filter, mounted on a printed circuit board and providing filtering for signals at hundreds of megahertz, typically comprises an input helical resonator having a helical winding and a series capacitive region and an output helical resonator having a helical winding and a series capacitive region. A conductive cover also mounted on the circuit board encloses both resonators and permits signal transfer from the input to the output resonator by means of inductive and capacitive coupling. Impedance matching between such an input or output helical resonator and a circuit connected thereto, some elements of which may be printed on the circuit board, has been achieved in the prior art by providing means for tapping the helical winding of the helical resonator. However, with such means the helical winding cannot be tapped at a precise point whereby attainment of optimum impedance matching is especially difficult.